Minimum till seeding knife

ABSTRACT

The present invention relates to a knife for and a method of zero till or minimum till seeding and fertilizing. The knife is particularly adapted for dry land conditions producing minimum solid disturbance and very shallow operation. The knife has a high penetration angle preferably of 45 degrees which permits the blade to enter high trash surface cover with little tendency to plug due to trash accumulation. The blade has a forward angle of attack, the lower cutting edge advancing before the upper cutting edge, serving to make a clean cut in the soil surface without accumulating trash. Seed and/or fertilizer conduits are attached to or incorporated in the trailing face of the blade in which the outlets may be spaced for controlled placement of the materials. By the method a furrow is cut having a substantial transverse component in an operation with a substantial forward component. A preferred embodiment includes a horizontal extension blade for cutting a horizontal swath at a shallow depth through weed growth. Conduits may be secured to the extension to allow greater separation and control of material placement. The knives may be arranged in overlapping configuration on the draw bar to affect weed cutting, seeding and fertilizing of a complete with of soil in a single pass.

CROSS REFERENCE TO RELATED APPLICATIONS

This Patent Application is a Divisional of, and claims priority to under35 U.S.C. §120, co-pending U.S. patent application Ser. No. 09/623,847,filed on Jul. 31, 2000, entitled, “Minimum Till Seeding Knife” andhaving Terry Emerson Summach and Bradley T. Summach as the Inventors.The full-disclosure of U.S. Patent Application Ser. No. 09/623,847 ishereby fully incorporated by reference.

FIELD OF THE INVENTION

The present invention relates to a method of farming, a farm implementand a knife or knife assembly which may be used as part of no-till orminimum-till farming practices primarily for placement in the ground ofseed and/or fertilizer and other materials. The invention works in allfield conditions, and in particular it operates with minimum soildisturbance in minimum till and zero till farming practices, betterallows passage of trash in such practices, and does not cause thehair-pinning of crop residue as is often caused by disc-type openers. Asa result, the method provides a simple, reliable and inexpensiveprocedure and tool which can be used in all farming practices so thatmultiple types of equipment are not required by farms for various soilconditions.

BACKGROUND OF THE INVENTION

Important advantages have been found in soil preparation, and seed andfertilizer delivery in employing no-tilling or minimum tilling methodswhich cause minimum disturbance to the soil. This is particularlyimportant in dry land conditions where the soil is subject to moistureand topsoil loss if conventional tilling methods are used.

It is usually desirable when employing no-till farming practices todisturb the soil surface as little as possible. The surface will becovered with the residue from previous crops, and the surface layer willcontain old root structure. This plant material can serve to retainmoisture below the surface and to assist in securing the soil againstrunoff and erosion. Particularly in dry land conditions it is beneficialto retain this covering. Tools available to seed into zero till orminimum till conditions have encountered problems.

Fertilizing prior to seeding is a method utilized by some farmers. Whilebroadcasting the fertilizer on the surface is a method that does notdisturb the surface, it is very inefficient, as much of the fertilizercan be lost due to runoff surface water. Placement of fertilizer at alevel well below the level that seed will be place has been utilized.Tilling and fertilizing is disclosed in Great Britain patent No.1,574,412 issued to Ede in 1980. In that prior art device an angledtilling blade for deeply penetrating the soil is shown with a centralduct and a number of separated orifices for providing fertilizer invertically separated bands. To maintain those desirable characteristicsof the surface structure in zero till conditions major surfacedisturbance is not acceptable.

Zero till devices have been developed to deposit high concentrationbands of fertilizer in furrows. If the seed is placed in close proximityto a high concentration of fertilizer, burning of the newly germinatedplant will result. To avoid this one technique has been to separate theseeds by a soil layer from the fertilizer.

In the U.S. Pat. No. 5,396,851 issued to Beau jot in 1995 fertilizer isdeposited by a first vertical blade which cuts a deeper furrow. A secondblade cuts a second furrow in which to deposit seed. Other devices suchas disclosed in U.S. Pat. No. 4,798,151 issued to Rodrigues in 1989 forma deep fertilizer furrow, and a shallower-shelf above the fertilizer onwhich to plant the seed. In both cases, to minimize soil disturbanceonly a narrow furrow is cut. It is grown to prepare soil when usingtraditional tilling methods to cut out weed growth prior to or at thetime of a seeding operation.

U.S. Pat. No. 1,085,825 issued in 1914 to Rubarth discloses a subsurfacetilling blade for use with a traditional turning plowshare. The tillingblade its curved to angle the cut and includes a horizontal blade on theopposite side. The blades are shown to include an arrangement inoverlapping fashion to cut the full width of the subsurface to removeweeds and old growth. Seeding and fertilizing are separate operations.

U.S. Pat. No. 5,005,497 issued in 1991 to Kolskog discloses a deepbanding knife for delivering seed and fertilizer with an additionaltransverse rod for disrupting weed growth. The banding knife makes asubstantially vertical cut in the soil. The rod disrupts the subsoil toloosen soil and cut weeds. The transverse rods can be arranged inparallel to remove weeds completely.

Adaptations of these concepts have been used for deep placement offertilizer in fully tilled row-crop situations.

In traditional zero till farming practice, no till furrows are separatedby undisturbed areas of soil and weeds. Typically a herbicideapplication is necessary to control weeds which would otherwise competewith the crop growth and possibly contaminate the harvest. Herbicide isan expensive additional operation.

A further problem encountered by seeding implements particularly in zerotill conditions is the accumulation of trash during seeding whichimpairs their operation. Many devices for seeding in zero tillconditions provide a blade which penetrates the soil substantiallyvertically. Trash gathers around the blade and is dragged with thedevice. This can impair operation. It also removes the desired moistureretaining cover. In an effort to combat this problem the Beau jotdiscussed above is adapted to lift over obstacles, such as crop stubble,interrupting seeding. Such a technique reduces trash accumulation, butreduces seeding efficiency.

A deep sowing tool has been disclosed for rice seeding in relatively wetconditions in USSR patent No. 372,962 issued in 1973 using a tillingblade and deep seed delivery to cover seeds and to reduce the need towater. This is not suitable for zero tilling, as tilling using this toolis deep in order to cause deep soil aeration. The blade of this priorart design penetrates the soil essentially vertically, with an angledblade portion cutting more deeply. The blade portion of this designwould also be subject to accumulation of trash.

Significant soil disruption occurs as vertical furrow parting tools aredrawn through surface soils at relatively high velocity, especially inhigh trash conditions or with unprepared soils. Additional energy isimparted to the soil, throwing and turning the soil.

It is desired for minimum soil disruption to pass through the soilsurface and any trash cleanly without undue lifting or turning of thesoil. While disk openers have the ability to cut through most trash,some straw will not cut easily, and is pushed into the furrow, a resultcommonly called hairpinning. This can displace seeds, as well as dryingout the seed bed. As well, effective no-till disc opener designs arerelatively expensive.

The prior art fails to provide teaching to or a suggestion of any methodor device for operation in zero or min-till conditions which providestilling and/or seeding, fertilizing or weed clearing in a single passwithout significantly disrupting the soil or the order of the soilstructure and avoid hairpinning. It is desired to provide the advantagesof tilling seeding and weed clearing without trash accumulation.

SUMMARY OF THE INVENTION

The invention provides a ground opening knife for use in no-till orminimum-till farming operations primarily in conjunction with seedand/or fertilizer placement adjacent a soil cut-line generally in thedirection of travel comprising connection mechanism adapted to mount theknife on a farm implement, and a blade comprising a lower portion, saidlower portion adapted to open soils along the direction of travel, saidlower portion adapted to extend into the soil but no more than 6 inchesmeasured vertically, said lower portion adapted to be oriented in adirection having a 1^(st) component of between 30 and 60 degrees belowhorizontal in a plane transverse to the said direction of travel, and a2^(nd) component forward in the direction of travel.

The knife may include an upper portion adjacent said lower portionadapted to extend away from the surface of the soil and is adapted topass through materials or residue on the surface of the soil orassociated with the passage of the knife though the soil.

The knife may also include an extension extending substantiallylaterally from said lower portion and provides support for materialdelivery tubes at various locations along the blade and extension.

The knife may also include in extension to form a secondary furrowadjacent the said lower portion intermediate the surface of the soil andthe lowermost end of the said blade and may include an extension of saidleading edge generally forward in the direction of travel.

The invention also provides a method of no-till or minimum-till farmingoperation primarily in conjunction with seed and/or fertilizer placementadjacent a soil cut-line aligned generally in the direction of travelcomprising forming a furrow in the soil extending from said soilcut-line no more than 6″ into the soil measured vertically, and formingthe said furrow by cutting the soil along a direction having a 1^(st)component of between 30 and 60 degrees below the horizontal in a planetransverse to the said direction of travel, and a 2^(nd) componentforward in the direction of travel.

The method substantially minimizes any disturbance of the cut soileither above the said furrow or below it or both whether distribution orparticulate or other materials is included at the same time within thefurrow being formed.

The invention also provides a no-till or minimum-till farm implementprimarily for use in conjunction with cultivation or materials placementadjacent a plurality of soil cut-lines generally parallel and in thedirection of travel comprising a support frame structure, a plurality ofaround opening knives attached to said support structure, spaced fromeach other in a direction transverse to the direction of travel of theimplement and each adapted to cut the soil along adjacent ones of saidcut-lines, each said knife having a blade comprising a lower portion,said lower portion adapted to extend into the soil but no more than 6inches measured vertically between the surface of the soil and thelowermost extremity of the said blade, said lower portion adapted to beoriented in a direction having a 1^(st) component of between 30 and 60degrees below horizontal in a plane transverse to the said direction oftravel, and a 2^(nd) substantial component forward in the direction oftravel.

The farm implement may include an extension of the blade extendinglaterally across a substantial portion of said spacing between adjacentsaid cut-lines when viewed in a plan view.

The invention will be more clearly understood to those skilled in theart with the following detailed description of preferred embodimentswith reference of the following drafting's in which:

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a plan view of a single knife according to the presentinvention;

FIG. 2 is a side view of the embodiment of FIG. 1;

FIG. 3 is a front view of the embodiment of FIG. 1;

FIG. 4 is a plan view of a further embodiment according to the presentinvention;

FIG. 5 is a side view of the embodiment of FIG. 4;

FIG. 6 is a front view of the embodiment of FIG. 4;

FIG. 7 is an isometric view of the embodiment=of FIG. 4 arranged on animplement for operation; and

FIGS. 8-1 through 8-3 are front, top and side elevations respectively ofanother embodiment of the invention adapted for double shooting ofmaterials in seeding. Like references are used throughout to designatelike elements.

FIG. 9 is a plan view of an agricultural implement for planting seeds.Which incorporates the seeding knives of the invention;

FIG. 10 is a horizontal front elevation of an angled seeding knife, inuse;

FIG. 11 is a side elevation of the knife of FIG. 10, from the left sideof FIG. 10, and FIG. 11 includes a cross-section on the line X-X of FIG.10;

FIG. 12 is a rear elevation of knife of FIG. 10;

FIG. 13 is a right side elevation of the knife of FIG. 10;

FIG. 14 is a cross-section of a blade of the knife of FIG. 10, thecross-section being taken in a plane at right angles to a knife-edge ofthe blade;

FIG. 15 is a front elevation corresponding to FIG. 10 of another angledseeding knife;

FIGS. 16, 17, 18 are further elevations of the knife of FIG. 15;

FIG. 19 is a pictorial elevation of a replaceable tip, of the knife ofFIG. 15;

FIG. 20 is an elevation of the body of the knife of FIG. 15, and isshaded to show the configuration thereof.

DETAILED DESCRIPTION OF THE INVENTION

The preferred embodiment of the single knife of the present invention isas shown generally at 10 in FIGS. 1-3. In FIG. 1 arrow designated 1shows the direction of travel of the knife through the soil whenworking.

As shown in FIG. 7 the knife 10 is typically attached to acultivator-type frame or implement generally indicated at 2 in FIG. 7 tobe towed by a tractor in a direction of travel 1 primarily incooperation with a tow-between or tow-behind seed supply carrier (notshown) having a repository of seed, fertilizer or other material andfluid passages for connection with the knife 10. The frame 1 is shown ingeneral online only.

The knife 10 includes a shank 12 which serves as a connection formounting the knife 10 selectively on the implement in a known fashion(as at 3 in FIG. 7). As shown in FIG. 7 an appropriate spacing 4 forseeding or tilling operations will be selected, determining the numberand spacing of knives 10 mounted across the width of the implement. Theshank 12 preferably has a pair of holes 13 for mounting bolts or themounting could be provided in any conventional manner such as a knock-ontaper mounting system or other known mounting mechanism.

Knife 10 includes a blade 14 formed to penetrate the soil along asoil-cut line 11 oriented in the direction of travel penetration of thesoil occurs at an angle A which has both substantial lateral (A1) andforward (A2) components of approximately 35-55=degrees=to the surface 5of the soil to be tilled preferably each of lateral and forwardcomponents A1 and A2 respectively is 45 degrees. Soil penetration is bythe lower portion of the blade as at 6 in FIG. 3 and is no more than 6inches, consistent with minimum till or no till farming practices.

The lateral component A1 of angle A determines the final angle of thefurrow cut into the soil. The angled furrow allows seed to be plantedensuring soil cover.

The blade is also angled significantly forwardly by component A2 ofangle A. Preferably lower end 17 of the cutting edge 16 is significantlyin advance of the upper end 15 of the cutting edge 16. Deeper soil iscut and lifted in advance of cutting the surface soil allowing thesurface to be cut along cut-line 11 more easily and without unduelateral disruption. Vertical motion is limited. The forward component ofangle A of the blade cuts through the surface and trash layers lastwithout accumulating trash on the knife 10. Leading edge 16 ispreferably continuous form its lower end 17 to its upper end 15.

The blade 14 had a leading cutting edge 16 and a pair of opposing angledsurfaces 18 a and 18 b which form a wedge shaped profile. The profileshape is determined by the furrow opening required. Edge 16 may be in 2parts, 1 below the surface and another above but preferably extendscontinuously above the surface sufficient to move trash and othermaterials aside without accumulation. Also preferably it is formedaligned with the leading edge of the lower portion of the blade.

Preferably surface 18 b is inclined slightly from the horizontal toavoid sliding contact with the soil below the blade 14 and minimize soildisturbance below the cut.

Also preferably, the rear surface of blade 14 is also angled forwardlyand downwardly so as to assist in the creation of a small temporarycavity behind the blade as it travels through the soil.

The overall effect is to provide a method and knife whereby primarilyvertical motion is imparted to the soil to permit the blade 14 passageand then a return substantially vertical motion is permitted whereby thesoil may return to its approximate original location.

Adjacent the trailing surface 20 of the blade 14 a conduit 22 may besecured for delivering seeds or other material.

The conduit 22 may have an outlet 24 near the lower end 17 of the blade14 as shown in FIGS. 1 and 2, and as a result the outlet 24 is adjacentthe lowest area of the furrow cut by the blade 14. The seed deliveryconduit 22 is protected from damage as the blade 14 is advanced throughthe soil by the blade body 14. The outlet 24 is also shielded frombecoming clogged with earth by this arrangement.

Additional conduits along the blade for fertilizer, herbicide or othermaterials may be similarly located (not shown in FIGS. 1-3)

The preferred method provides the steps of forming and angled no-till orminimum till furrow by a knife which furrow cutting motion has both asubstantial forward and a substantial lateral component both above andbelow the ground to a depth of 6 inches.

In a preferred method, seed and fertilizer are scattered from adjacentoutlets in a pattern across the width of the furrow. The outlets may bespaced apart to appropriate depths and separation, for example, placingfertilizer outlet at the lowest end of the blade for the deepestapplication and a seed outlet spaced above it on the angled blade 14.

Another preferred embodiment is shown in FIG. 8 in which FIG. 8-1 showsthe embodiment in a front view, FIG. 8-2 in a plan view and FIG. 8-3 isa side elevation.

In FIG. 8 the embodiment is shown in conjunction with the knife andmethod shown in FIGS. 1-3 with an additional double shoot extension 8.Leading edge 16 of the lower portion 7 is extended further forward anddownward as best depicted in FIG. 8-3. As seen in the front view of FIG.8-1 this will provide a secondary furrow or ledge intermediate thesurface of the soil 5 and the lower end 17. FIG. 8 show this embodimentas forming a v-shaped furrow particularly suited to the deposit ofparticulate material such as seed which would be retained in thisgroove. The extension 8 could have other shapes to form a ledge or othershape as required.

An extension 8 depends from lower surface 18 b, extension 6 may beprovided with a delivery conduit 19.

This double shoot method forms a seed or other material positioningshelf or secondary furrow within the angled furrow with a specificspacing from the lowermost extremity.

An alternate embodiment of the invention is shown in FIGS. 4-6. Theknife 10 includes a blade 14 as described above. The knife 10 furtherincludes an extension blade 30 that extends substantially horizontallyform the blade 14 preferably at its lowermost end 17. The extensionblade 30 has a leading cutting edge 36, which preferable forms acontinuation of or 3^(rd) part if leading ledge 16. Edge 36 issubstantially horizontal and is preferably oriented transverse to thedirection of travel. The cutting edge 36 is formed between an uppersurface 32 angled upwardly and rearwardly and a lower surface 33 whichis substantially horizontal. The lower blade surface 33 may preferablybe angled to the rear, upwardly about 2 degrees, or notched, to reducedrag.

The extension blade 30 increases the pertain width of the knife 10 asshown in FIG. 7. This extends the cultivating and/or planting area forgreater seed bed utilization, or may be selected for greater spacingbetween seed planting while still effectively cutting existing plantroots to condition more of the width of soil. The extension blade 30 maybe varying width for different spacing considerations.

Outlets for seed, fertilizer and other addictives may be spaced apart inor on the extension blade 30 to form distinct rows (not shown) and arepreferably adjacent the rear surface thereof or may provide forbroadcast across the width of extension 30.

Outlets may also be placed at the corner between the angled blade 14 andthe extension 30 as at 24 on FIGS. 4 and 5, or higher on the angledblade 14, for vertical separation, such as for herbicide applicationnearer the soil surface.

As seen in FIG. 7, a plurality if knives shown including extension 30 onan implement frame in outline may be arranged spaced in continuous oroverlapping arrangement on the implement 2 so that the full width ofsoil is conditioned. The number and spacing will depend on the crop andplanting conditions. Suitable placement of outlets along extension 30would result in a generally scattered seed and fertilizer delivery inbehind each knife 10. In this case the complete width of the soil mayalso be cut by the blade extension without being dragged and fouling theknife 10.

The extension blade 30 may be positioned to travel under the path of theangled blade 14 of the adjacent knife 10.

Knives 10 are mounted to an implement or cultivator frame as in FIG. 7.A wing section of the frame is illustrated in outline form. Additionalcentral and wing sections are not shown. The frame is carried on loadsbearing wheels (not shown) which support the frame in a raised positionfor travel and in operative position.

Adjustment of the height if the frame in a known fashion accuratelycontrols furrow depth. Depths may typically range from ½ inch to 4inches or up to 6 inches. Alternatively, a ground following linkage maybe used to attach each knife to the frame, with the depth beingcontrolled by a wheel attached to each knife assembly.

In use the knifes 10 arranged in parallel fashion on an implement oroverlapping arrangement on an angled draw bar are drawn by a tractortogether with a seed carrier provided with reservoirs of seed andfertilizer material and a fluid delivery system operatively connectedwith the conduits 22 on the knives 10. The frame 2 is advanced with theleading cutting edges and, optionally, 36 facing in the direction oftravel 1. The deposit of material is controlled to the sped of advanceat the tractor in a known fashion.

The knife 10 will not normally produce overlapping furrows without theblade extension 30 being present, or being long enough to result in anoverlapped cut with adjacent rows as the placement would be too close.Weed control with herbicides is necessary in those circumstances.

As seeding occurs, fertilizer can be added simultaneously in controlledconcentration, or at a desired depth or spacing from the seed.Fertilizer is more efficiently used without loss from runoff. Furtherfertilizer is placed to be available to the crop and not at the surfacefor weeds. A substance delivery of fertilizer is particularly effectiveif gaseous fertilizer, such as ammonia, is used. The knife provides avariety of options for placement with minimum adjustment and cost.

It may be desired to seed an area progressively in time for continuousharvest. Or with different additives, or with different crop. Since theprocess is a complete single pass operation, each seeding will includecomplete weeding and fertilizing more accurately than if separate stepsare made which might leave areas untouched.

The invention may also be used as a light tilling tool for minimum soildisturbance without seeding or fertilizer outlets. This would cut weedsand provide minimum soil aeration. The knife advantageously does notturn the soil which would incorporate weed seeds from the surface intothe soil to germinate.

Additional embodiments of the present invention will be apparent topersons of skill in the art.

FIG. 9 is a plan-view diagram of an implement 120 which carriesthirty-five angled-knife seeders 123 in four rows. The implement 120 hasa centre section 124, and two hinged wings 125. The wings 125 can befolded upwards for road-transport and storage of the implement. Thecentre section 124 includes a hitching mechanism 126 whereby theimplement can be towed by a tractor.

It will be noted that some of the angled-knife seeders 123 slope to theleft, and some to the right. Thus, there is no, or only a small, netsideways force on the implement. The left seeders and the right seedersare kept separate. In banks, since the configuration of the seeders isnot suitable for close-pitched left-right mountings thereof.

Press-wheels 127 are provided. One in-line behind each seeder to rollover. And to close the ground. After the seeds have been deposited bythe seeders.

The seeders are attached each to a respective mounting bar 128, which issuspended from the frame 129 of the implement, the suspension mechanismincluding the usual break-back-spring mountings 130.

FIG. 10 is front view of one of the angled-knife seeders 123. FIG. 10shows the seeder being dragged forwards, i.e. out of the paper, asindicated by the arrow 132. FIG. 11 is a lateral or side elevation,showing the seeder being drawn through the ground, and moving to theleft as indicated by arrow 132. FIG. 11 includes an inset cross-section,taken on line X-X of FIG. 10; it is emphasized that line X-X isvertical, i.e. the inset cross-section in FIG. 11 lies in a verticalplane.

As shown from the front view, FIG. 10, the seeder or knife 123 has anangled blade 134 which extends down into the ground to a depth,typically of about 10 cm. The depth is determined by the needs of thetype of seeds being planted; planting seeds deeper than 10 cm would beunusual, and 15 cm can be regarded as a maximum planting depth.

The angled knife cuts an angled slit-opening in the ground, and theseeds are deposited therein. The seeds to be planted are sullied from ahopper on the implement, and are blown along a hose by mechanism of afan which forces an air flow in the hose. The hoses are of flexibleplastic tubing, one for each seeder (the hoses are not shown in FIG. 9).

Each flexible hose is clipped to a respective conduit 135, which isbuilt into the seeder 123. The conduit is structurally integrated intothe back-side of the angled-knife-blade 134, and runs down the back-side136 of the blade. The conduit ends in a discharge mouth 137, from whichthe seeds emerge, and fall down into the slit-opening. The dischargemouth 137 is near the bottom of the knife blade, whereby the seeds aredeposited more or less at the bottom of the slit opening.

The conduit 135 is shown in the rear view of the seeder, FIG. 12, and inthe opposite side-elevational view to FIG. 11, FIG. 13. The upper end ofthe conduit terminates at a port 138, into which the flexible hose canbe secured.

The knife blade has an over-surface 139 and an under-surface 140. Thesesurfaces are respective plat planes. Which meet at a line. That linebeing the knife-edge 142. The blade is generally triangular incross-section. In that the surfaces 139, 140 slope back from the knifeedge, to a maximum thickness of the blade at the back-side 136 thereof.The conduit 135 is accommodated within the thickness of the back-side ofthe blade.

FIG. 14 is a cross-section of the blade 134 and shows the dimensionsthereof. The FIG. 14 cross-section is taken in a plane at right anglesto the knife-edge. The dimension 143 is the distance between theover-surface 139 and the under-surface 140 at the back-side if theblade, which in this case is 32 mm; and dimension 145 is the distancefrom the knife-edge 142 to the mid-point of the conduit 135, which inthis case is 70 mm. The conduit 135 has an internal diameter if 24 mm.The angle between the over-surface 139 and the under-surface 140, in thecross-section at right-angles to the knife-edge, is called the wedgeangle 146, which in this case is 25 degrees.

Not only is the angled blade 134 angled to the side, at aside-slope-angle 147, as shown in FIGS. 10 and 12, but the blade is alsogiven a forward pitch angle 148, as shown in FIGS. 11 and 13. In thiscase, the side-slope angle 147 is 45 degrees, and the forward pitchangle is also 45 degrees.

The leading knife-edge 142 is positioned such that when the blade isviewed from in front. Only the over-surface 139 can be seen. Theunder-surface 140 is invisible. That is to say, the knife edge is at thelowermost point of every vertical cross-section taken through the blade134. Thus, the portion of soil that lies in the path of the blade liesin the path of the over-surface 139 of the blade. The over-surface hasthe wedge angle 146, and the soil is therefore driven upwards, by thewedge angle. The uplift travel of the soil is determined by the verticalheight 149 of the over-surface 139, as presented to the oncoming soil,which in this case is about 8 cm.

FIG. 15 is a front elevation of another design of angled-knife seeder150. In this case, the above-ground portion of the seed conduit 152 ispositioned to one side of the above-ground shank 153. This location ofthe conduit provides access for the nuts and bolts which are used at 154to fix the seeder to the mounting bar 128 however, although access forthe nuts and bolts is good, the extra width of the shank 153 mechanismthat the shank can be obtrusive, and can cause soil debris created bythe passing of the angled blade to hang up; it might be regarded thatthe wide shank can act like a bulldozer blade.

A deflector surface 156 is provided, for deflecting soil debris awayfrom the front face of the shank 153. The deflector surface is angled todeflect the debris downwards, and to the side. The nub 157 serves alsoto break the upward flow of the debris, and to keep the shank 153 clear.

It may be noted that, in FIG. 1, the triangular gusset-surface 159 wasdisposed at an angle that included a downwards component, and so thegusset-surface 159 also served to deflect up-flowing debris downwards,and sideways, away from the shank 12 of the knife. Thus, thedeflector-surface can be on the outside (FIG. 15) or the inside (FIG. 1)of the angle between the shank and the blade. Providing downward-facingdeflector surfaces on both the inside and the outside also is possible,except that the designer should take care that the knife is not weakenedthereby, at the transition 160 (FIG. 15), 162 (FIG. 1), between theshank and the angled blade.

FIGS. 16, 17, 18 are other views of the knife of FIG. 15. It will benoted that this knife includes a separable and replaceable tip 163. Thetip shown separately in FIG. 19. FIG. 20 is a shaded view of the back ofthe body 164 of the knife, and shows not only how the conduit in thisdesign is molded into the shape of the knife, but shows also a spline165 on the body, which forms the mounting base for the replaceable tip163. The tip is held to the spline 165 by mechanism of a pin whichengages the pin-receiving-hole 167. The spline is prism-shaped, having atriangular cross-section like that of the blade itself, but smaller, andthe tip includes a socket that is complementary to the conduit. Oncepinned in place, the tip is very securely constrained against all modesof movement relative to the body 164. The pin serves only to keep thetip from falling down the spline, but the force tending to make the tipmove in that mode minimal: all the heavy forces between the tip and thebody are supported by the chunky spline 165.

The conduit 152 continues inside the spline 165. It is important thatthe seeds are deposited close to the bottom of the cut opening; with theconduit inside the spline, even though the bottom part of the knifecomprises the tip, the conduit goes to the bottom of the opening. (Itwould be inefficient to cut the opening deeper that the planting depthsof the seed, so the discharge mouth of the conduit should be as near thebottom of the knife as possible.) On the other hand, the prudentdesigner would seek to avoid calling for the manufacture of a (tubular)extension of the conduit in the tip casting. Putting the conduit in thespline puts the discharge mouth of the conduit more or less at thebottom of the trench, even though the knife has a replaceable tip.

It will be noted that the lower extremity 168 of the knife edge 169 onthe body 164 is rounded convexly, whereas the upper extremity 172 of theknife edge 170 on the tip 163 includes a tag 173 which is roundedconcavely. Thus, debris traveling up the knife edge can readily passsmoothly over the transition between the two knife edges 196,170. Thedesigner should see to it that the knife edges do not containinterruptions, upon which soil-debris could be snagged. Forming the body164 with a large convex radius is easy from the casting-manufacturestandpoint; it is much easier to control the quality of aconcavely-curved tag on the tip casting than on the body casting.

The knife edge 170 in the tip 163 can be blunter than the knife edge 169on the body. The tip operated more deeply, where debris, even ifimperfectly cut, tends to be brushed off the knife edge by the pressingpassing soil. On the body, the knife edge itself has to do all thecutting of debris and vegetation, with little assistance from thepassing soil, since, being shallower, the passing soil might more easilybe deflected. It is noted that, if it happened, a hang-up of imperfectlycut material on the knife edge would be a quite serious problem, as itwould quickly lead to disruption and disturbance of a large area of soilaround the slit opening.

Conventionally, when seeding has been done with seeding knives (asopposed to discs, etc) the seeding knife has been held vertically. Whenthe seeding knife is held at a side-slope-angle, as described herein,the manner in which the soil is opened for receiving the seeds isconsiderably changed.

When the knife is at a side-slope-angle of about 45 degrees to thehorizontal, what happens is that a flap 174 of soil is liftedtemporarily by the passing blade 134, and then the flap is loweredgently back after the seeder knife 123 has passed. As a result, thelayers of the soil are preserved, during seeding. In other words, it ispossible for a farmer to plant seed without disturbing thestratification of the soil. It may be noted that the press wheels 127serve to press the flap 174 back down, and assist in the maintenance ofstratification: thus the function of the press wheel is more in harmonywith the action of the angled blade, than in the case of a press whenlinked with, for example, a non-angled (vertical) seeding knife.

Maintenance of soil stratification is important in currently-favoredminimum-till farming regimes, because moisture in the layers a fewcentimeters down is not dissipated; weed seeds on the surface remain onthe surface and do not germinate; and stalks and vegetation at thesurface remain intact, providing cover and moisture retention. On theother hand, the angled knife, especially when a wing extension isprovided below ground, cuts and severs the roots of any vegetation thatmight be present, whereby weeds and unwanted plant growth are destroyedsimply by mechanical action. Using herbicide to destroy weeds isexpensive and can be dangerous, and has to be done as “reach” of theangled knife can be enough to sever the roots of weeds and other growthnot only around the seed openings, but over the whole area of groundbetween the openings.

The fact that the flap of soil is pushed upwards by the angled bladedoes not mean that the soil is compressed: if the soil were pusheddownwards or sideways, it would become compressed and perhaps smeared,since there is no where for the deflected soil to go; but when the soilis urged upwards, the soil simply moves upwards. Of course, liftingdeeper soild would involve lifting the weight of all the soil above, solifting without compression only works down to shallow depths. Thus, itwould not be possible to lift a flap of soil without compressing it ifthe soil were more than 10 or 15 cm deep. But it is recognized that seedplanting is done predominantly at shallower depths than that; and it isrecognized that the depths down to which an angled blade can cause thesoil to simply lift without being compressed is a suitable depth toenable planting of nearly all types of seeds.

If the knife were nearly vertical, i.e. if the knife were angled over atmore than about 60 degrees to the horizontal, the lifting action thatoccurs with the angled knife would become negligible. With the 45-degreeangle, most of the movement of the soil that occurs is a riding up ofthe soil over the front edge of the knife. Ay 60 degrees, the soil tendsto be bulldozed, or chiseled, rather than slit or cut. Insofar as thesoil is pushed to the side by the knife, the soil is compressed, andsmeared, rather than gently lifted.

Of course, the knife must emerge from the ground surface, and the veryshallow soil around the point of emergence inevitably is lifted toomuch, and tends to fly away. However, this effect is less disturbingthan inserting a vertical chisel into the ground.

If the knife were more nearly horizontal, this fly-away lifting of theshallow soil might be too much. Besides, if the knife were nearlyhorizontal, although the knife would still lift the flap of soil, theknife blade would need to be too long in order to get down to the seedplanting depth, which would mean that too much soil was being moved fora given planting depth, and which would be poor mechanically.

Tests have shown that the slap-lifting, stratification-maintaining,advantageous effects of the angles blade are largely lost if the bladeis angled (i.e. the side-slope-angle) more than about 55 degrees or lessthan about 35 degrees. 60 degrees and 30 degrees can be regarded as thepractical limits. It has been found that the force required to draw theangles blade through the ground is at a minimum when the blade is atabout 45 degrees. It may be noted that the minimum draw force is anindication of minimum ground disturbance, which is what makes forminimum-till agriculture.

The leading knife-edge of the angled blade should be lowermost into theground. That is to say, the soil approaching the blade should “see” onlythe over-surface of the blade. Thus, all the soil that is deflected isdeflected upwards. If some of the soil were driven downwards, orhorizontally sideways, it would be compressed or smeared, and seeding ismost effective and efficient when the seeds are placed on and in soilthat has not just been compressed.

The effective but gentle lifting as desired has been obtained withangled blades where the blade has been so presented that theover-surface has been about 7 cm high, measured in a vertical sense,from the leading knife edge to the back of the over surface. (Thethickness of the blade, measured in a plane at right angled to theleading edge, preferably is between 25 and 45 mm.) The angle between theover-surface of the blade and the under-surface, called the wedge angle,is a key factor in determining the lift of the blade, and good resultshave been obtained when the wedge angle lies between 20 and 30 degrees.

Preferably, the over-surface should be a single flat plane over itswhole area, but it is recognized that it id the front of theover-surface of the blade that is key to the performance, i.e. the front4 cm of the over-surface contiguous with the knife edge.

Preferably, the blade is generally triangular as to its cross-sectionalshape, the three sides of the triangle being the over-surface, theunder-surface, and the back-side of the blade. (The back-side is not, asshown, a flat plane.) It is recognized that the triangular is a goodshape, in that it leads to a suitable angle for the over-surface of theblade, in order for the over-surface to deflect soil dynamically; also,the bottom face can be easily set to not touch the soil passing-byunderneath the blade; also, the bottom face can easily be set to nottouch the soil passing-by underneath the blade; also, the thickback-side has to be thick to accommodate the conduit. In short, thetriangular shape is a highly efficient shape for performing thesoil-moving operations required for seeding, for accommodating the seedconduit, and (not least) is a food shape for providing mechanicalstrength and rigidity in just the right amounts for the task.

The designer should see to it that the knife is reasonably short, in thetravel direction. Length would just lead to extra drag, and perhapssmearing of the soil, the aim should be to combine efficient use ofsurfaces and angles to give smooth lift-then-fall-back movement of thesoil, without disturbing the soil, and while maintaining stratification.The designer should see to it that the surfaces are angled enough, andare long enough for that, and of course the knife has to be strong andrigid enough to be struck occasionally by stones etc without beingdamaged. It is recognized that the angled blase as described herein is adesign that handles these conflicting requirements very advantageously.

The conduit preferably should be in the size range of 15 to 25 mmdiameter, for proper seed conveyance. It is recognized that such a sizeof conduit is wee-suited to being located behind the triangular angledblade, as described. The blade surfaces, i.e. the over-surface and theunder-surface, slope towards the conduit as two simple flat planes,straight from the knife edge.

As mentioned, the functions of the blade require that the blade be wideenough for its surfaces to be so angled as to be effective; and theblade must also be strong enough; beyond that, the blade shouldpreferably be short. Good results have been obtained when the blade isabout 7 cm, or at least between 5 cm and 10 cm, in width, from theknife-edge to a mid-point inside the conduit.

The blade should have forward pitch to ensure the soil debris can clear,by riding upwards along the knife edge, and out of the soil. It willhappen sometimes that some material are not cut, or not cut immediately,by the knife edge, and will be piled up ahead of the knife edge, therebyblunting the knife edge. The angled knife should have forward pitch tocounteract this. Of course, conventional vertical seeding knives havehad forward pitch.

Preferably, the seed conduit should be integral with the knife unit. Ifseparate, the conduit has to be attached to the knife unit. The conduitshould not get in the way, not least above ground, where the conduit cancontribute to snagging of soil debris. Therefore, the conduit should liein line behind the knife. Whilst this is clearly achievable below theground, above ground putting the conduit in line with the knifestructure is not so good, because the shank of the knife is attached tothe mounting bar by bolts passing through from front to back, andputting the conduit behind the shank would deny access to thebolts/nuts.

The designer also want the point of attachment of the flexible seed hoseto be high, out of harm's way, and also wants to provide room for a clipfor attaching the hose into the conduit. The designer either can put theconduit on a stalk that protrudes out behind the shank (which suitsfabricated construction (FIG. 2)), or can put the conduit to one side ofthe shank (which suits casting (FIG. 16)). Or, the conduit may befinished lower down, below where the shank is bolted to the mounting bar(FIG. 11), although now the flexible hose might be vulnerably close tothe ground. Putting the conduit to one side of the shank (FIG. 16) givesaccess to the fixing bolts, but now the front face of shank is therebywidened, so it is even more important to take measures against snaggingof the above-ground soil debris on the shank.

One of the benefits of the angles blade configuration lies in theability to deposit two types of items simultaneously, e.g. seeds andfertilizer, which preferably should be kept spaced apart, upon planting.Simultaneous deposition of both seeds and fertilizer (FIG. 8) issimplified by the fact that the knife is at an angle, while ensuringsame are kept spaced apart. If the knife were vertical, both items wouldfall to the bottom of the trench, and it would be difficult to keep theitems apart. On vertical knife seeders, it is conventional to provideside ledges; for fertilizer, however, the protrusions on the verticalknifes that produce such side ledges have also compressed the soil.

Generally, the farmer wishes to plant as many rows of seeds as possiblein a single pass if the seeder implement. In one of the machinesdescribed herein, thirty-five seeders are provided-on a singleimplement. The smallest number that might practically be contemplatedwould be about eighteen seeders per implement. The large number ofseeders is appropriate for single-pass seeding operations at shallowdepth, in that a tractor can easily provide the force necessary to drawa large number of shallow seeders through the ground. This may becontrasted with the conventional usage of angled cutters to break uphard-pan sub-soil, i.e. caked clay and soil some 50 cm or more belowground. Sometimes, these deep angled-cutters have been used to prepareground for seeding, but in that case the seeding has been doneseparately, as a follow-up seeding operation, using conventional seeddrills. (Breaking up hard-pan also can be done for other purposes, e.g.to improve drainage.) The conventional large, deep, hard-panangled-cutters were angled simply in order to cover more ground. Theywere constructed so as to cause maximum disturbance to the soil, at alarge depth; they required large forces to draw them through the ground,so that only a small number, say four to five, could be pulled by atractor. The use of an angled blade as described herein to lift shallowflaps of soil with minimum disruption, and to lower the soil flap backdown without disturbing stratification, makes a clear contrast with theuse of deep angled cutters to break up hard-pan. It is emphasized thatthe gentle, minimum-till, operations described can take place only atshallow depths.

In the above aspects, the invention is defined by reference to animplement, in which the angled blades are mounted for operation, Inanother aspect, the invention can be defined with respect only to theknife unit itself, independently of the implement. In this case, thedefinition makes use of the shank of the knife, and of the axis of theshank. When the shank is provided with two bolts, one above the other,for attachment to the mounting bar, the shank axis (in a frontal view ofthe shank) is the line that runs through the bolts. However, even if theshank is mounted by mechanism other than two bolts vertically in-line,the shank still has an axis, which can be determined by the geometry ofthe shank in a particular case. The major features of the invention, theblade lies at an angle to the shank in front view, and the shallow depthof the blade, are present in this definition.

As mentioned above, sometimes the conventional vertical knife seedershave included, as an accessory, a mechanism for providing a side ledgeto the vertical trench. As mentioned, grains of fertilizer are depositedon or in this side ledge, whereby the fertilizer can be kept spacedapart from the seeds. The fertilizer rests on the ledge, while the seedsfall down to the bottom of the vertical trench.

An example of such vertical-knife-with-side-ledge structure is depictedin Canadian patent publication CA-2,099,555(Henry, 1995). Henry'sstructure includes a first conventional vertical knife-blade 25, forcutting a vertical slit in the ground, with the associated delivery pipefor depositing seeds at the bottom of the vertical slit. Henry alsoshows a ledge-cutting accessory 28 the accessory 28 is fixed to the backof the vertical knife-blade 25. Thus, in the design as depicted in FIGS.5 a,5 b of Henry, two injectors are shown: one for injecting seeds, andthe other for injecting fertilizer.

Regarding Henry's vertical knife-blade cutter/fertilizer-injector: whenviewed from the side (FIG. 5 a), Henry's knife blade 25 is angled, suchthat the bottom extremity of the knife-blade leads the rest of theknife-blade as the knife-blade travels through the ground. It isconventional, and very common, for vertical seeding-trench knife-bladesto be angled forwards, i.e. bottom-edge leading. In the front view (FIG.5 b), Henry's knife-blade 25 is not angled at all.

Regarding Henry's side-ledge cutter/fertilizer-injector: when viewedfrom the side (FIG. 5 a) Henry's ledge-cutter 28 is so angled as to be“bottom-edge-trailing”. That is to say, the bottom extremity of theledge-cutter lags, or trails, as the ledge-cutter travels through theground. In the front view (FIG. 5 b), Henry's ledge-cutter 28 makes anangle to the horizontal of about 45 degrees.

Neither of the blades or cutters of Henry will achieve the “gentleup-and-over” effect, which is the aim of the present invention. This isbecause neither of the blades or cutters of Henry has an over-surfaceand an under-surface, which meet at a line, where the line defines theleading knife edge of the blade, and where the knife edge, thus defined,has a side-slope angle of between 30 degrees and 60 degrees.

Defined with the respect only to the knife unit itself, independently ofthe implement. In this case, the definition makes use of the shank ofthe knife, and of the axis of the shank. When the shank is provided withtwo bolts, one above the other, for attachment to the mounting bar, theshank axis (in a frontal view of the shank) is the line that runsthrough the bolts. However, even if the shank is mounted by mechanismother than two bolts vertically in-line, the shank still has an axis,which can be determined by the geometry of the shank in a particularcase. The major features of the invention, that the blade lies at anangle to the shank in front view, and the shallow depth of the blade,are present in this definition.

1. Agricultural knife apparatus, which is so structured as to be suitable for inserting materials such as seeds into the ground, wherein: the apparatus is structurally suitable for the operation of creating a slit-opening in the ground and of inserting the materials into the slit-opening, at a depth that is less than about 15 cm vertically below the ground surface; the apparatus includes a shank and a blade, and includes a transition zone, at which the shank and blade are joined integrally; the shank includes a front surface and a rear surface, and left and right side surfaces; when viewed in front elevation, the shank has an axis, termed the shank axis; the blade is formed with an over-surface and an under-surface, which intersect at a line, and the line defines an angled-knife-edge of the blade; the shank axis intersects the line of the angled-knife edge, at a point of intersection on the angled-knife-edge; when viewed in front elevation, the line of the angled-knife-edge slopes at an angle, termed the knife angle, relative to the shank axis, and the knife angle is between 30 and 60 degrees; the angled-knife edge has a bottom extremity thereof, and the distance, measured along the angled-knife-edge, from the point of intersection to the bottom extremity of the angled-knife-edge, is less than about 30 cm.
 2. As in claim 1, wherein the angled-knife-edge is a straight line.
 3. As in claim 1, wherein the knife apparatus includes a conduit, which is structurally suitable for depositing seeds in the ground, the conduit being attached to, or supported upon, the blade on a back-side of the blade, which is opposite to and remote from the knife-edge.
 4. As in claim 1, wherein, in a cross-section of the blade portion taken in a plane at right angles to the knife-edge, the over-surface and the under-surface make an included angle of intersection of between 15 and 30 degrees.
 5. As in claim 4, wherein the included angle of intersection is the same at cross-section taken in all planes between the point of intersection and the bottom extremity.
 6. As in claim 1, wherein the shank includes an attachment mechanism for attaching the knife apparatus to a mounting bar, the attachment mechanism includes two bolt holes, one above the other, in the shank, and the axis of the shank passes through the bolt holes. 